JPS6019985A - Multistage pump - Google Patents

Abstract

PURPOSE:To select a relative position in a peripheral direction as well as to adjust the form of a curving flow passage so as to improve its efficiency at an operating point, by making up a guide vane and a flashing vane in a guide device with a separate member, respectively. CONSTITUTION:A guide vane 6a and a flashing vane 6b both are made up of a separate member each and joined together at a contact surface 6d. In this device, water flowing out of an impeller 5 flows along the guide vane 6a, then its swirl is controlled by the flashing vane 6b by way of a curving flow passage comprising a guide device 6 and an intermediate casing 7 and flows into the next step impeller 5. In case of a small water quantity, since a mainstream of the flow is much in an axial component, it flows as in a zigzag line. In case of a large water quantity, however, as the mainstream of the flow is much in a peripheral component, causing it to become rectilinear, whereby the guide vane 6a and the flashing vane 6b are shifted as far as a portion for X in the peripheral direction and optimized in adjustment of the form of the curving flow passage 13 to a direction of the mainstream.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a multi-stage pump, and more particularly to a guide device comprising a guide vane and a return vane for a multi-stage pump.

[Background of the invention]

In multi-stage pumps, a method is generally used in which a guide device is built into the ring-shaped casing in order to reduce the face-to-face dimension of the first stage and the overall length of the pump. The submersible deep well pump will be explained below. FIG. 1 is a vertical cross-sectional view of an example of a conventional submersible deep well pump, and FIG. 2 is a detailed vertical cross-sectional view of the guide device of the pump shown in FIG.

In FIG. 1, reference numeral 1 denotes a pump driving mold, and a mold shaft 3 is coupled to a pump shaft 4 by a coupling 2. As shown in FIG. A plurality of impellers 5 are fixed to the pump shaft 4 according to the required discharge pressure, and the impellers 5 are rotated by the moder 1. As the impeller 5 rotates, water is drawn in from a suction strainer 14 provided between the mold 1 and the pump, and is energized by the impeller 5. The water passes through a guide device 6 arranged behind the impeller 5 and reaches the next stage impeller 5, whereupon the discharge pressure is increased and the bearing casing 8. It is discharged through a pen casing 10 containing a check valve 9. The structure and operation of the guide device will be explained based on FIG. 2. An intermediate casing 7 partially extends toward the impeller 5 fixed to the pump shaft 4, and a liner ring 11° 12 at the tip forms a water flow path as a narrow gap with the impeller 5. . A guide device such as a guide vane 6a and a water return vane 6b is provided in this flow path. The water flowing out from the impeller recovers the dynamic pressure component in the energy given by the impeller 5 to static pressure by the guide vanes 6a, and at the same time reduces the swirling flow by the water return vanes 6b, so that the water flows to the next vane. He is sent to car 5.

Thereafter, the energy is applied by the impeller 5 and the static pressure is restored by the guide device 6, while the discharge pressure is increased and the discharge is performed as described above. Such a pump is called a multistage pump.

On the other hand, JIS stipulates standard well diameter and pump maximum outer diameter, and since the guide vane outer diameter cannot be made large enough, the guide vane 6a and water return vane 6b of the guide device are It is configured to have a continuous flow path, thereby ensuring a diffuser effect and at the same time smoothing the flow between the water return blades 6b.

However, in the flow path connecting the guide blade 6a and the water return blade 6b (hereinafter referred to as the flow path), due to the restriction of the outer diameter, the dynamic pressure component of the total pressure of the water discharged from the impeller is static pressure is not fully recovered, and the shape of the curved flow path affects the magnitude of hydraulic power loss.

FIG. 3 shows the flow pattern of this curved channel.

When the amount of water is small, the main stream of the flow is as shown by the solid line, and when the amount of water is large, the main stream of the flow is shown as the broken line. In this way, the flow pattern of this curved flow path changes within the pump specification water flow range, so it is difficult to create an optimal flow path for each water flow, and at a certain water flow, the flow pattern and flow path shape may not match well. However, this method has the drawback of causing separation and vortices in the flow, increasing hydraulic power loss and deteriorating pump performance.

In addition, as shown in FIG. 4, a guide blade 6a and a water return blade 6
In some cases, b is created separately, but in this case, it is not a continuous flow path but constitutes a space 6C, which has the disadvantage that the outer diameter of the pump becomes large.

[Purpose of the invention]

The purpose of the present invention is to alleviate the drawbacks of the prior art as mentioned above,
A multi-stage pump that can improve pump efficiency with an optimal flow path pattern when the water volume is specified by the customer, and can also change the flow path pattern to improve operating point efficiency when the flow rate specifications change. is to provide.

[Summary of the invention]

The multistage pump according to the present invention has a guide vane and a water return vane, and has a flow path through which water discharged from the impeller flows continuously from between the guide vanes to between the water return vanes. It is characterized by the fact that the return feathers are separated from each other.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a guide device for a multistage pump according to the present invention will be described in detail based on drawings of embodiments. FIG. 5 is a detailed longitudinal sectional view of an embodiment of the guide device for a pump according to the invention. In this guide device, the guide blade 6a and the water return blade 6b are formed as separate members, and are joined at a mating surface 6d. Other points are the same as the conventional device shown in FIG. 2, so the same parts are designated by the same reference numerals and their explanation will be omitted. In this device as well, the water flowing out from the impeller 5 flows while remaining in the guide blade 6a, and then passes through a curved flow path consisting of the guide device 6 and the Uma Kusinga, and is prevented from turning by the water return blade 6b. It flows into the impeller 5 of the next stage.

FIG. 6 is an explanatory diagram of the state of flow in the curved flow path in FIG. 5, viewed from the outer circumferential surface of the guide device. Figure 6 (a) shows the relative positional relationship between the guide vane and the water return vane according to the flow turn when the flow is small, and Figure 6 (b) shows the flow turn when the flow is large. The relative positional relationship between the guide vane and the water return vane is shown below.

13 is a curved flow path.

In the case of a small amount of water as shown in FIG. 6(a), the main flow has a relatively large axial component, so it flows in a meandering manner as shown by the arrow. In the case of a large amount of water as shown in Fig. 6(b), the main flow of the flow has many circumferential components and is linear as shown by the arrow. Shift it,
The shape of the flow path 13 is optimized according to the direction of the main flow.

FIG. 7 shows a characteristic diagram of an embodiment of the pump of the present invention. The solid line and the broken line are curves of the efficiency η and the head H when the positional deviation between the guide vane and the return vane (X in FIG. 6) is large and small. As is clear from FIG. 7, as the positional deviation between the guide vane and the return vane increases, the maximum efficiency of the pump shifts toward the larger water volume side, and the total head also increases at the larger water volume side.

Therefore, the pump can be operated most efficiently by assembling the pump by setting the positional deviation amount X between the guide vane and the return vane to an optimal value for the customer's specified water flow rate. Note that the amount of deviation X between the guide vanes and the water return vanes may be adjusted before assembly as described above, or, for example, the water return vanes may be made movable in the circumferential direction and connected to a fixed member by an elastic body, and this elastic body may be adjusted. It may be automatically adjusted based on the balance between the force and the rotational force in the circumferential direction of the water return blade due to water pressure.

〔Effect of the invention〕

As explained above, in the multistage pump of the present invention,
Since the guide vanes and water return vanes of the guide device are made of separate members, the relative position in the circumferential direction can be selected appropriately, and the shape of the curved flow path can be highly efficient at the operating point (customer specification point). Therefore, the high efficiency operation range of the pump can be expanded.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of an example of a conventional submersible deep well pump, Fig. 2 is a detailed longitudinal sectional view of the guide device of the pump shown in Fig. 1, and Fig. 3 is a longitudinal sectional view of an example of a conventional submersible deep well pump.
The figure is an explanatory diagram of the state of flow in the multi-flow path viewed from the outer circumferential surface of the guide device, and the figure 4 is an explanatory diagram of the flow state in the multi-flow path as seen from the outer circumferential surface of the guide device.
FIG. 5 is a detailed longitudinal sectional view of the guide device in the embodiment of the pump of the present invention, and FIG.
Fig. 7 is an explanatory diagram of the flow state in the case of a small amount of water in the curved channel (Fig. a) and in the case of a large water cover (Fig. b), as seen from the outer peripheral surface of the guide device. Fig. 7 is an embodiment of the pump of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Mordle, 3... Mordle shaft, 4... Pump shaft, 5... Impeller, 6... Guide device, 6a... Guide vane, 6b... Water return vane, 6d. ... mating surface,
7... Intermediate coushing, 11.12... Liner ring, 13... Multi-curve passage, 14... Suction strainer. Agent Patent Attorney Tadashi Akimoto Figure 1 Figure 2 2.3 3 Figure 4 Figure 5 Cause 6d 6a 9J 6

Claims (1)

[Claims] In a multistage pump having a guide vane and a water return vane, and a flow path through which fluid discharged from the impeller continuously flows from between the guide vanes to between the water return vanes, the guide vane and the water return vane are A multistage pump characterized by being composed of separate members.